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The site is a rock shelter well up on the western side of Bishop's Cap, an outlier of the Organ Mountains. It lies about 450 ft below the summit according to Brattstrom (1964); this would make its elevation about 1500 m. It was originally excavated by the Los Angeles County Museum (LACM) ca. 1929 (LACMVP site number 1010). Specimens collected from talus, fill, or other areas are labeled 1010 Dump or 1010D. Specimens collected by Conkling are labeled C 1010. The shelter was excavated in 5-foot sections.

Brattstrom (1964) had access to the original field notes. Two profiles were given. One in Sec. S-5-7, from bottom to top: rock bottom of the shelter, 5" angular fragments, 8" smooth concretionary limestone fragments mixed with brown dust, 6" of ash mixed with angular fragments, 10" of layered gray (volcanic?) ash grading into a layer of brown, 4" of hard burned guano, 4" of unconsolidated bat guano, top. Most bones were found in brown and gray ash. Another section 53" thick, from bottom up: floor of the shelter, 17" of broken concretionary limestone fragments, 16" of brown ash, 12" of gray layered ash grading into the brown below it, 8" of bat guano, top.

Brattstrom (1964:95) gives several quotes from the original field notes: Sloth in place, S-5-4 in upper guano layer and in direct association with bits of knots of vegetative material. S-6-5, sloth bone in upper yellow layer. Mummified rat and snake on top of rocks in bat guano. S-5-6, S-5-5, horse jaws in brown ash. S-5-6, sloth skull fragment in gray ash below overhanging rock. In same section above rock was an Indian grindstone. S-4-7, beads and sandal found beneath guano layer and also below overhanging rock. S-4-9, badger and deer skulls in gray ash.

Rancholabrean (late Pleistocene) and Holocene. One date on sloth dung (Van Devender and Spaulding 1979) of 11,330 ± 370 BP (Before Present). Material has continued to accumulate up to the present. Thompson et al. (1980) list three dates for sloth dung, including that above; the others are 12,330 ± 190 and 12,430 ± 250. They also list dates on Desert Tortoise (Gopherus agassizii) scutes and bone (11,280 to 12,520) and dates for middens of packrats in the shelter (11,850 to 31,250).

Fosberg (1936) lists plants identified from Shelter Cave deposits, but without provenance data; they likely are Holocene. He also mentions that there are coprolites of either sloth or horse. Thompson et al. (1980) point out that vegetation from pre-full-glacial middens from the shelter are more mesic than the terminal Pleistocene ones that lack oak, and pinyon pine is rare.

Harris, A. H. 1977. Wisconsin age environments in the northern Chihuahuan Desert: Evidence from the higher vertebrates. pp. 23–52, in Transactions of the symposium on the biological resources of the Chihuahuan Desert region, United States and Mexico (R. H. Wauer and D. H. Riskind, eds.), Natl. Park Serv. Trans. Proceedings Series 3:1-658.